Batteries in hybrid electric vehicle applications operate from partial state of charge and are subjected to short periods of charge and discharge with high currents. High-rate discharge is typical of engine cranking, while high-rate charge is usually associated with regenerative braking. High-rate charge and discharge pulses typically associated with these operating conditions are prone to inducing chemical side-reactions that consume or impede the reactions of some of the active chemicals. In particular, during charging, the potential of the negative electrode may become negative to such extent that hydrogen ions in the solution are reduced, leading to a reduction in charging efficiency and in the unwanted production of hydrogen gas. The production of gas may in turn lead to increases in cell pressure, creating a danger of cell rupture or leakage. Suppression or mitigation of hydrogen gas production would therefore be beneficial to both the performance and operational life of lead-acid batteries.